Contact device for miniature impulse motors



25, 1970 w. J. HANHART 3,525,836

CONTACT DEVICE FOR MINIATURE IMPULSE MOTORS Filed July 5, 1961 INVENTOR.

WI! #61 /l //4/V//A .07

BY Ml 1,6541

United States Patent 3,525,836 CONTACT DEVICE FOR MINIATURE IMPULSE MOTORS Wilhelm J. Hanhart, Schwenningen (Neckar), Germany Filed July 5, 1961, Ser. No. 122,017 Int. Cl. H01h 3/6'0, 5/20 US. Cl. 200-466 9 Claims ABSTRACT OF THE DISCLOSURE The invention relates to a contact device for miniature pulse motors, in particular to oscillating motors. Such motors usually reveal a unilaterally clamped contact spring which comes into conductive contact with a movable opposite contact for a short time during the rotation, for example, during a given oscillation frequency of the motor armature, and is elastically deformed thereby, i.e. bent. The movable counter contact is usually a pin associated with the motor armature. The contact springs consist mainly of nickel or of inert metals, in order to improve the conductivity and the passage of current.

As is well known, the assurance of a good contact presents great difficulties, both with regard to the adjustment of the contacts initiation and also with regard to the control of the contacts termination during the movement. In view of the fact that the better is the passage of current the higher contact pressure, the contact pressure has been increased as far as possible. This increase in contact pressure has, however, certain set limits, particularly in view of the smallness of the unit in question, in order not to raise the frictional and deformation forces beyond a proper limit. Above all, however, the inevitable result of the above is that the spring contacts are too rigid and are therefore inclined to oscillate or to vibrate and to thereby frequently interrupt the contact during the current transfer time. These result in poor current consumption. Since the impulse oscillating motors are usually fed or energized by small dry batteries, there is made too great a demand on the batteries thus resulting in a considerably decreased usefullness.

It is the object of the invention to overcome the above disadvantages. It consists in the provision, in a contact device for impulse oscillating motors, of a unilaterally fixed clamped contact spring and a counter contact actuated directly or indirectly by the motor armature, the free end of said fixed contact, which is made of good conducting material and which comes in contact with the movable counter contact, being covered with a firmly adhering insulating coating on both sides. This coating is so dimensioned that it makes the contact closing between the contact spring and the counter contact only after a certain angle of deflection of the contact sprign.

The provision of the firmly adhering insulating coating or sheath is to prevent the closing of the current circuit at the first contact of the contact spring with the movable contact, so that it closes only after a certain deflection of the contact spring. It is thus possible to materially 'ice dampen the oscillations or vibrations of the contact spring by an appropriate calculation of the gap between the insulating layer and the contact-making end, to so arrange the deflection angle until contact is made, that the oscillations or vibrations of the contact spring will be materially decreased.

In series manufactured impulse oscillating motors it is possible to arrange by corresponding attempts, as above, the most favorable position of the insulating layer. This layer consists, for example, of insulating lacquer firmly applied in a corresponding position.

If there are several difierent types of motors on hand and it is desired to make a precise adjustment, then the insulating layer may be made as an insulating sleeve which, for example,- encloses both sides of the contact spring, the sleeve being arranged adjustably and clamped on the free end of the contact spring.

The insulation layer placed over the free end, is under some circumstances insufficient for each length, material and kind of the contact spring, to prevent the abovementioned contact interruptions through vibrations. Therefore, according to a further important feature of the invention, in addition to the described insulation covering, there are provided between this latter and the clamp of the contact spring, one or more damping elements, which are so calculated and located that they practically fully restrain the above named self-induced oscillations of the contact spring.

The additional damping elements may be disposed on one or both sides on the contact spring, fixedly or movably for adjustment, and may be emplaced adjustably on the contact spring. They may consist, for example, of plastic, insulating lacquer, rubber or similar insulating materials.

When several damping elements are present, these may be constructed alike or dissimilarly according to kind and size and may be adjustable or non-adjustable, in order to dampen not only the basic, but also some harmonic oscillations of the contact springs.

In the simplest type of a practical embodiment and in the serial production according to investigations, the damping elements may consist of an air-dried insulating lacquer applied in concentrated form.

In the accompanying drawing, there is shown, by way of example, a preferred embodiment of the invention.

It should be understood, however, that such embodiment is given by way of illustration and not of limitation and that many other variations of the device are possible, without departing from the scope of the invention.

In the drawing:

FIG. 1 is a plan view of the device and FIG. 2 is a side view thereof.

Referring now to the drawing in detail, there is shown in dotted lines the armature 1 of an impulse oscillating motor, the shaft 2 of which is borne by a point above a fixed housing part in an adjustable screw 4. A contact pin 5 is fixedly secured to the oscillating armature 1, which, according to each direction of oscillation comes in contact with one or the other side of a contact spring 6 which is tensioned on one side. This spring is secured detachably and adjustably to housing part 3 by means of an insulated carrier clamp 7 and is connected with a lead 8 to a battery (not shown).

The contact spring 6 has on its free end an insulation cover 9, which fully encloses it and which consists of baked on insulation lacquer, and begins in a gap a from the outer end of the contact spring 6. The gap a is so chosen that when it is first struck by contact peg 5, no contact results at first, the latter occurring rather only after a predetermined angle of inclination. Until this happens, the rebounding oscillations are nearly completely dampened.

The self-induced oscillations of the contact spring 6, evoked by the rebounds of the contact spring 6 are restrained and made ineffective by means of, for example, damping member 10, of an air dried insulating lacquer applied in convex form.

The illustrated embodiment of the invention, which, in its initially disclosed form, may be changed, has proven itself very suitable.

The passage of the current ensues during the continuous movement, from the start of the contact until the separation of the contact pin and contact spring, with an even contact pressure and without interruptions and reverse currents. Through a previous series of oscillographic investigations, the contact cover and the damping element were so ascertained that as a matter of fact the undesirable damage and contact interruptions were completely eliminated.

With devices in use heretofore, the oscillograms of the contacts course indicated a number of strong current peaks, which at first disappear gradually and pass into a straight line, only to show some smaller current fluctuations at the end, i.e. at the separation of the contact. These undesirable interruptions and fluctuations produce a quantitatively irregular current impulse, apart from the previously described unwholeso'menesses, frequency variations and in the case of chronological arrangements impermissible deviations from the time standard.

In contrast thereto, with the contact device according to the invention, the oscillagraphic record of the contact course indicates an ideal rectangular shape of current curve.

What I claim is:

1. A contact device for miniature impulse motors particularly for oscillating motors, comprising, a contact pin, means oscillating said pin in a predetermined path, a flexible conductive element having a fixed end and a free contact-making end, said element formed with an insulated portion of predetermined shape and measurement, spaced from said contact making end, said pin during its travel engaging with said insulated portion when said element is in normal undeflected position and with said contact-making end when said element is bent by said pin to an angle of deflection from said normal undeflected position said angle determined by the shape and measurement of said insulated portion and by its distance from the contact making end.

2. In an oscillating motor, a motor armature, a contact pin secured to said armature for oscillation therewith, a housing member, an insulated clamp mounted on said housing member, a flexible conductive element having one end fixedly mounted in said clamp, said element disposed in the path of travel of said pin, said element having a free contact making end, an insulating sleeve of predetermined shape and measurement mounted on said element and spaced a predetermined distance from said contact making end, said pin during its travel engaging with said insulating sleeve when said element is in normal undeflected position and with said contact making end when said ele- 3. In an oscillating motor, a motor armature, a contact pin secured to said armature for oscillation therewith, a housing member, an insulated clamp mounted on said housing member, a flexible conductive element having one end fixedly mounted in said clamp, said element being disposed in the path of travel of said pin, said element having a free contact making end, an insulating sleeve of pre determined shape and measurement, adjustably mounted on said element in locking engagement and spaced a predetermined distance from said contact making end, said pin during its travel engaging with said insulating sleeve when said element is in normal undeflected position and with said contact making end when said element is bent by said pin to an angle of deflection from said normal unment is bent by said pin to an angle of deflection from said deflected position, said angle determined by the shape and measurement of said insulating sleeve and by its distance from the contact making end.

4. In an oscillating motor, a motor armature, a contact pin secured to said armature for oscillation therewith, a housing member, an insulated clamp mounted on said housing member, a flexible conductive element having one end fixedly mounted in said clamp, said element being disposed in the path of travel of said pin, said element having a free contact making end, an insulating sleeve of predetermined shape and measurement mounted on said element and spaced a predetermined distance rom said contact making end, said pin during its travel engaging with said insulating sleeve when said element is in normal un deflected position and with said contact making end when said element is bent by said pin to an angle of deflection from said normal undeflected position said angle determined by the distance of said insulating sleeve from said contact making end and by the shape and measurement of said insulating sleeve, said element further provided with at least one damping member disposed between said clamp and said contact making end for damping resonant oscillations upon impact of said pin on said element.

5. The device according to claim 4, further provided with an additional damping element secured to said element.

6. The device according to claim 5, wherein said damping elements are adjustably secured to said element.

7. The device according to claim 1, wherein said insulated portion consists of lacquer.

8. The device according to claim 5, wherein said damping elements consist of plastic materials.

9. The device according to claim 4, wherein said damping element consists of lacquer in a convex-shaped form.

References Cited UNITED STATES PATENTS 1,368,785 2/1921 Cosgray 200166 1,937,403 11/1933 Davies 200-90.3 2,265,297 12/1941 Little 200-l66 2,502,339 3/1950 Perreault 200166 2,838,693 6/1958 Van Horn 20090.3 2,671,864 3/1954 Vaulry 31039 2,685,655 8/1954 Vaulry 310-39 HERMAN O. JONES, Primary Examiner 

